Iprovement in slide-valves of steam-engines



UNITED STATES PATENT OFFICE.

JOHN B. ROAHCH, ELIZABETHPORT, NEV JERSEY.,

lIMPROVEMENT IN SLIDE-VALVES OF STEAiVI-ENGiNES.

Specification forming part of Lettcrs'Patent No. 36,797, dated October528, 1862.

To all whom it may concern.-

Be it known that I, JOHN B. ROAOH, of Elizabethport, in the county ofUnion and State of New Jersey, have invented a new and usefulImprovement in the Slide-Valves of Steam-Engines; and I do herebydeclare that the following is a full, clear, and exact description ofthe same, reference being had to the :accompanying drawings, forming,part of this specification, in which- Figure 1 is a central longitudinalsection of the Valve-chest and slide-valve of an engine, having myimprovement applied. Fig'. 2 is a transverse section of the sax-ne.

Similar letters of reference indicate corresponding parts in the twogures.

The object of this invention is to provide for what is termed thebalancing of the valve.- that is to say, to relieve it of unnecessarypressure toward its seat.

To'enable others `skilled in the art to make and use my invention, Iwill proceed to describe its construction and operation.

A is the valve-chest, a a the valve-seat, and b b a smooth plane surfaceprovided inside the back or cover of the chest, parallel with the seat aa. The surface b b may be on the back or cover of the valve-chest, orupon a separate plate of `sufficient stiffness secured within the chestat the back of the valve.

B and C are `the two pieces of which the valve is composed. The piece Bhas its face, which works upon the seat a a, of a form correspondingwith that of an ordinary short double slidevalve, and contains the usualexhaustcavity,r. The sides and ends of the said piece B areperpendicular with its face, and its back, which is fiat, has aninclination to the seat in a transverse direction, as shown at c c inFig. 2, but is parallel therewith in a direction lengthwise of thevalve, as shown in Fig. l. The piece C, which is arranged between thepiece B and the back of the valvechest, is made with its two facesparallel in a direction lengthwise of the valve, as shown in Fig. l, butinclined to eachother in a transverse direction, as shown in Fig. 2, insuch degree that it may fit accurately between the surfaces c c and b b,so that no steam may get betweenitandthesurfacebb. The said piece C,being so formed and tted to the back of the pieceB, with inclined planesurfaces, is capable of operating between the latterpiece and thesurface b bas a wedge, and thereby adj usting the Vlatter to the seat aa, while it adjusts `itself to the surface b b, and thereby, while itconnes the face of the piece B to the seat, protects the back of it fromsteam-pressure.

It should be observedthat the area of B and C, measured in a directionparallel with their face and back, should be about equal. The drawingsrepresent C as narrower ,than B,

(see Fig. 2,) in order to allow it sufficient movement in thatdirection, but represent it Y passes through a slot, h, in the piece@and screws into the piece B; and to provide for the setting of the pieceC, to adjust the valve to the seat a a and face b b, I provide on thepiece B a lug, z', in which there is a tapped hole for the reception ofa screw, j, and provide in the pieceC a mortise, k, for the reception ofthe said lug. IThe screw j is inserted through a hole provided for it onthe thicker side of the piece C, audits head bears against the exteriorof the said piece, as shown in Fig. l. In the back of the valve-chestthere is pro' vided a tapped hole fitted with a screw-plug, Z, which ismovable for the admission of a screw-driver to turn the screw-bolt g,and in the proper side of the chest there is a similar hole fitted witha screw-plug, m, which is movable for the admission of a screw driver toturn the screw j These holes provide for the adjustment of the valvewithout taking off the cover of the steam-chest.

When it is desired at any time to adjust the valve, the engine isstopped with the valve in such position that the bolt g and screw j areopposite to the plugsland m, which will be known by the engineer. Thescrew-plugs are then removed, and the bolt g slackened to liberate thepiece C, which in then 'adjusted by turning the screw j. When theadjustment has been made, the boltg is screwed up tight again, and thescrew plugs replaced. rIhe adjustment may be so made that the valve willWork steam-tight between the surface of the seat a d and the surface I)b, and yet with so slight friction that there will be very little Wear,either of the Valve or of the said surfaces; but when suiicient Wear hastaken place to cause leakage of steam it may be easily compensated forby setting in the piece C, as above described. The great advantage ofthis construction of the Valve is its extreme simplicity as comparedwith most of the balanced valves in which Wear is provided for.

` I do not claim making a valve of tapering` form laterally, as that maybe found described in Patent No. 13,923; neither do I claim,

broadly, constructing a'valve of two or more parts adjustable relativelyto each other and to the Valve-seat, and to a surface parallel to theValve seat, as several examples of such construction may be found; but

What I claim as my invention, and desire to secure by Letters Patent,is- A The combination of the two inclined pieces, B C, andadjusting-screws j g with each other 'and with the Valve-seat a a andback b b, in

the manner herein shownk and described.

JOHN B. ROAGH. Vitnesses:

J. SnErLn, f J. EDWARDS MARSH.

